Index: wp-admin/includes/upgrade.php
===================================================================
--- wp-admin/includes/upgrade.php	(revision 8202)
+++ wp-admin/includes/upgrade.php	(working copy)
@@ -93,7 +93,7 @@
 	// First post
 	$now = date('Y-m-d H:i:s');
 	$now_gmt = gmdate('Y-m-d H:i:s');
-	$first_post_guid = get_option('home') . '/?p=1';
+	$first_post_guid = $wpdb->get_var('SELECT UUID()');
 	$wpdb->query("INSERT INTO $wpdb->posts (post_author, post_date, post_date_gmt, post_content, post_excerpt, post_title, post_category, post_name, post_modified, post_modified_gmt, guid, comment_count, to_ping, pinged, post_content_filtered) VALUES ($user_id, '$now', '$now_gmt', '".$wpdb->escape(__('Welcome to WordPress. This is your first post. Edit or delete it, then start blogging!'))."', '', '".$wpdb->escape(__('Hello world!'))."', '0', '".$wpdb->escape(_c('hello-world|Default post slug'))."', '$now', '$now_gmt', '$first_post_guid', '1', '', '', '')");
 	$wpdb->query( "INSERT INTO $wpdb->term_relationships (`object_id`, `term_taxonomy_id`) VALUES (1, 1)" );
 
@@ -101,7 +101,7 @@
 	$wpdb->query("INSERT INTO $wpdb->comments (comment_post_ID, comment_author, comment_author_email, comment_author_url, comment_date, comment_date_gmt, comment_content) VALUES ('1', '".$wpdb->escape(__('Mr WordPress'))."', '', 'http://wordpress.org/', '$now', '$now_gmt', '".$wpdb->escape(__('Hi, this is a comment.<br />To delete a comment, just log in and view the post&#039;s comments. There you will have the option to edit or delete them.'))."')");
 
 	// First Page
-	$first_post_guid = get_option('home') . '/?page_id=2';
+	$first_post_guid = $wpdb->get_var('SELECT UUID()');
 	$wpdb->query("INSERT INTO $wpdb->posts (post_author, post_date, post_date_gmt, post_content, post_excerpt, post_title, post_category, post_name, post_modified, post_modified_gmt, guid, post_status, post_type, to_ping, pinged, post_content_filtered) VALUES ($user_id, '$now', '$now_gmt', '".$wpdb->escape(__('This is an example of a WordPress page, you could edit this to put information about yourself or your site so readers know where you are coming from. You can create as many pages like this one or sub-pages as you like and manage all of your content inside of WordPress.'))."', '', '".$wpdb->escape(__('About'))."', '0', '".$wpdb->escape(_c('about|Default page slug'))."', '$now', '$now_gmt','$first_post_guid', 'publish', 'page', '', '', '')");
 }
 endif;
Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 8202)
+++ wp-includes/post.php	(working copy)
@@ -1301,8 +1301,11 @@
 		clean_post_cache($post_ID);
 
 	// Set GUID
-	if ( !$update && '' == $current_guid )
-		$wpdb->update( $wpdb->posts, array( 'guid' => get_permalink( $post_ID ) ), $where );
+	if ( !$update && '' == $current_guid ) {
+		// get a UUID
+		$uuid = $wpdb->get_var('SELECT UUID();');
+		$wpdb->update( $wpdb->posts, array( 'guid' => $uuid ), $where );
+	}
 
 	$post = get_post($post_ID);